Tiny circular thin spot in the paper. Also known as bubble marks or steam
blisters.

Air Bubbles

Light spots in a sheet caused by bubbles of air that form in the stock on a
Fourdrinier wire (forming fabric) and are entrained in the stock as it
cascades in trays and channels. The term also refers to bubbles of air
formed in the coating operation and the defective imprint that is caused by
the bubble bursting.

Air Doctor Mottle

A paper coating defect caused by excessively high solid content or high
viscosity of coating solution or poor adjustment of doctor.

Air Knife Mark

A paper coating defect caused during the coating operation with an
air-knife coater, producing areas that are more transparent than the rest of
the sheet. They are called blade streaks when occurring in narrow areas
running in the machine direction.

Alum Spot

Paper sheet having small undissolved alum crystals.

Backing Roll Mark

A paper coating defect caused by the building up of coating in areas along
the machine direction where low spots occur in the coating back-up roll.

Backing Roll Mark

A paper coating defect caused by the building up of coating in areas along
the machine direction where low spots occur in the coating back-up roll.

Baggy Paper

A paper which is thicker in middle than edges.

Bark Specks

These specks originates from outer bark of wood.

Binder Specks

A variation in ink receptivity caused by non-uniform binder distribution. A
coated paper defect that results in a grainy or textured appearance on the
coated surface.

Blackening

A paper showing burn marks on the surface.

Lowering of opacity of paper as a result of uneven formation, too much
moisture, and crushing caused by too much during calendering. It produces
darkening effect on the sheet.

Blade Cut

A blade scratch that cuts deeply into or through the web.

Blade Marks

Paper coating defects caused at the time of coating operation with a blade
coater, producing areas which are more transparent than the rest of the
sheet. It is also known as air knife marks or blade streaks.

Blade Scratch

A very fine, hair like indentation in a coated surface that runs in the
machine direction, caused by a particle of varied origin becoming lodged
behind the blade during coating.

Blade Wrinkle

A blade coating defect where the sheet has been folded over on itself when
passing under the blade. It is irregular line essentially in machine
direction.

Bleach Scale

Used for pearly, light brown, brittle spots in paper.

Blemish

Undesirable marks on the surface of paper sheet.

Blistering (Coated Paper)

Caused when water vapours can not escape fast enough through coating layers
in the coating dryer section of the heat-set press.

Bristle Marks (Coated Paper)

Use for indentations in the surface of coated papers in the shape of brush
bristles.

Brush Marks (Coated Paper)

Used for streaks in the surface of coated papers made by brushes which
spread on the coating in the papermaking process.

Buckles

The edge of a roll, usually only part of the diameter, where the paper along
that edge is thinner and longer than the balance of the width of the paper on
the roll. To compensate for this extra length, it buckles as it is wound.

Burst

The defect in paper characterized by rapture in the web not extended to
edges. It is caused by too high web tension between a hard and soft section of
the reel during winding and results in a machine direction shearing force that
exceeds the strength of paper.

Calender Blackened or Calender Crushed

A paper whose color has been darkened because of calendering it while it is
still wet or with too much pressure. This crushes the fibers and disorients the
formation resulting in to darkened color and reduced opacity and surface
characteristics.

Calender Cut

A mark or cut occurring in the paper sheet as a result of wrinkles in the
web while being calendered.

Paper defects caused by faulty calender roll surfaces or extraneous matter
which has entered the nips and stick to its surface.

Calender Streaks

Are relatively high(er) gloss bands in the machine direction, resulting from
non-uniform wet pressing, drying, coating, etc, and these bands gloss more in
the calender.

Chalking

1. Breaking away of pigment from paper surface during finishing and
converting operation.

2. Rubbing off the ink pigment from printed paper surface.

Cloudy Paper

Paper with unevenness in look-through.

Coal Specks

It is a type of dirt. These are black, insoluble particles that are often
in a pulverized condition, as a result of the action of calender rolls.

Coating Defects

Coating streaks are continuous defects that may be very clear and long, but
they can be short and extremely narrow. Other coating defects are skips and
splashes. Skip can be very subtle and detection is the main problem. On the
other hand, coating splashes may provide a clear contrast with a specific
shape.

Coating Lump

A random piece of dried coating that has been redeposited onto the web of
paper.

Coating Mottle

A slight mottle created during the calendaring process due to a non-uniform
base sheet or coating process.

Coating Splash

Random spots of excess coating.

Cockling

When the surface of the paper has wave like appearance.

Contraries

Presence of any foreign substance such as sand, dirt etc.

Corrugation

Simply put, corrugations are accordion-like paper folds that form when the
web, strained beyond its yield point, cannot return to its original shape.
Corrugations can form on the paper machine, coater, calender stack or
winder. They are caused by a combination of an uneven distribution of weight
across the web and an uneven nip, which create strain.

Couch Marks

Defects which appear as a regular pattern, always when viewed by
transmitted light and sometimes when viewed by direct light. Cause is
usually some non-uniform water removal from the sheet of paper at the
suction couch roll and takes the pattern of the drilled hole in
suction couch roll.

Crack

1. A defect in coated paper, caused by the separation of
the coating layer on the formation of fissures in the
surface of the coating due to printing or other
converting process.

2. Crack at fold: Fissures in the crease when any paper
is folded along a fold line. May be due to separation of
coating or separation of fibers. More prevalent when the
paper has been over-dried. In boards it may occur along
score-folds even though the scoring has been done to
minimize cracking at the fold. The term is also applied
when coatings crack without fiber failure during a
folding operation.

Cracked Edge

A paper web and Fourdrinier wire defect occurring as small breaks on the
edges, with very little migration towards the center.

Crepe wrinkles are crease-like paper defects that occur mostly in newsprint
and LWC papers. Typically an 1/8-inch to a 1/4-inch wide, crepe wrinkles
generally form as a result of paper slippage in poorly built-up rolls, and
excessive caliper variation of the sheet. Once the excessive and localized
layer-to-layer slippage is momentarily blocked or interrupted, the wrinkle
is formed. Paper that is severely weakened in creped areas is doomed to
break in successive processes.

Crepe wrinkles can be found virtually anywhere in a roll, but primarily in
the areas below a splice after a web break. They also form at the outer
diameter of the roll during the rewinding process, as well as near the core.

Crush

A rippled paper surface defect that is caused by the use of too high
pressure and/ or too high moisture in the press section.

Curl

Papers which curl up when placed on a flat surface.

Damp Streaks

Streaks caused by uneven pressing or drying during paper
manufacturing.

Dandy Marks/ Dandy Pick

A defect consisting of a small, thin area left on the paper sheet due
to the disturbance or picking up of fibers from the web by dandy roll.

Dark Spots

Dark spots can be any kind of dirt or scrap. These are normally random
defects and it is very difficult to find their origin.

Dead Spots

Paper sheet having any dull areas in an otherwise highly glossy surface.

Delamination

Paper peeling apart or separating from within.

Dirt

Any foreign material that is unintentionally embedded into the sheet of
paper.

Drag Spots

Irregular streaks or long thin lumpy areas on the paper's surface.

Dust

Small particles of paper, fibers or coating materials that are found in a
finished roll of paper or at the edges of a skid.

Edge Cut

Edge tears fold over during the winding operation. It may be caused by dull
slitter that nicks the edge after which the stress of winding will cause the
tear to open or the reel is bumped on the edge.

Holes or weak spots in the finished paper caused by foam in the wet end
of the paper machine, or surface defects such as spots occurring in a coated
paper surface as a result of foam in the coating.

Fuzz

Fibrous projections on the surface of a sheet of paper,
caused by excessive suction, insufficient beating or lack
of surface sizing. Lint appears in much the same manner
but is not attached to the surface.

Haircuts

Hair-thin cuts in the surface of a sheet where it appears that hairs or
long fibers have been pulled out of the surface.

An irregularity in the ink coverage of a printed page.
Hickeys are caused by paper or pressroom dust, dirt, or
pick out on the printing blanket, all of which prevent
the ink from adhering to the paper surface.

Holes may be clean or with some dirt at the edges. Typical clean holes are
wire holes, calender cuts and edge cracks. If a hole is caused by foreign
material, that has been in the sheet and later fallen off, there still may
be some dirt left at the edge.

Reasons to slime holes are wet end slime, splashes of sizing material,
or even wet fiber lumps. The appearance of spot varies.

Iron Specks

It is a type of dirt. Iron specks can be determined by treating the speck
with 10% HCl acid solution and potassium ferrocyanide solution. If speck is
iron, it will turn intense blue. Rust specks are reddish brown to black in
color.

Lint

Lint originates from loosely bonded surface fibers. This is also called fuzz
or fluff also. Lint can cause fiber build up in the printed image areas when the
lint mixes with ink.

These are usually translucent specks which varies from amber to black in
color. These comes from undissolved resin.

Ridge

A ring around the circumference of a roll or an area in a skid of paper in
the machine direction that is harder or higher than an adjacent area; also
called hard spot.

Roping

Paper defect appearing as a machine direction wrinkle in the sheet.

Longitudinal wrinkles in a coated paper.

Seam Marks

Is a defect in the web, normally running at approximate right angles to the
machine direction and is seen as a light streak when viewed by transmitted
light. Point of origin is usually an article of machine clothing, a wire or
a felt, that is seamed. The distance from one defect to the other is a clue
as to the origin of the mark.

Shadow Mark

A defect in paper appearance which looks like the drilling pattern in a suction roll. It is due to
opacity effects caused by areas of vacuum and pressure as the wet web passes over a suction roll.

Shiners

Transparent spots in a sheet of paper caused by squeezing partly cooked
fiber bundles and splinters during calendering.

Slaps

Ruptured spots at the edges of machine-made papers.

Slime Holes

A hole in paper, characterized by brownish translucent material around the edges. Caused by a lump of slime which has formed in stock system from the growth
microorganisms, then becoming detached and flowing onto the paper machine wire with the fiber to form a non-fibrous area.

Slitter Dust

The accumulation of dust, primarily filler, fibers, or coating thrown off
during the slitting operation, and remaining on or in the roll.

Slivers and Shives

Shives are small pieces of wood that have been cooked but whose fibers are
not separated.

Slivers are small splinters of wood in a sheet of paper that have not been
cooked.

Snailing

Streaks or snake like marks on the surface of a sheet.

Soft Start

The foundation of any roll is the first few layers of paper on the roll’s
core. If those first few layers carry a low-level wound-in tension, a soft
start condition exists. Problems associated with soft starts include:

The bond between the paper and the core breaks causing a
loss of coupling with the unwind break.

Starring develops.

The roll tightens during unwinding, taking up loose
paper at the core. This layer-to-layer slippage causes crepe wrinkles
and breaks over the unwind core chucks

Spongy Papers

Paper that is too compressible or ink absorbent for its intended purpose.

Spots by Liquid Droplets

Liquid droplets cause spots, which have more regular shape than other
spots. Oil spots are so translucent that they may be mixed with holes.

Starring

Starring is a common structural defect that appears as a collapse near the
core of the roll. Caused by uneven stress distribution inside the roll, the
starring or collapse of paper is initiated once a portion of the roll, which
is wound with a low wound-in tension, increases and a ring or hoop of
tightly wound paper causes a collapse of the softer wound interior. A highly
unstable situation, virtually any outside blow can collapse the highly
stressed ring into its softer foundation.

While most collapses are usually local and involve only two or three lines,
more severe collapses can damage the paper in the fault area and require the
roll be unwound. A starred roll is very difficult to unwind because it loses
its concentricity. Because of severe tension fluctuations, the operator has
to reduce the speed of the secondary process. If the roll is too damaged to
rewind, recycling it is the only alternative.

Stickies

Stickies are tacky substances contained in the paper pulp and
process water systems of paper machines. Stickies have a large tendency to
make deposits on the processing equipment in certain stages of the
papermaking process. Contaminations of paper that that are classified as
tacky are also called stickies. The main sources for stickies are recycled
paper, waxes, and soft adhesives.

Table Rolls Mark

Basis weight variations of web caused by waves on the wire created by table
rolls.